1. Field of the Invention
The present invention relates to a fluid feeder, a balloon catheter and a fluid feeder supporting device which are employed by feeding fluid into a balloon.
Priority is claimed on U.S. patent application Ser. No. 12/046,744, filed on Mar. 12, 2008, the content of which is incorporated herein by reference.
2. Description of Related Art
In general, various types of balloon catheters provided with a balloon in the vicinity of a distal end of the catheters are employed in a medical field, for example, urological catheters provided with a balloon for medical use such as indwelled urinary catheters, endotracheal tubes, digestive tract catheters and cardiac balloon catheters for cardiac pumping (for example, U.S. Pat. No. 6,267,717, U.S. Pat. No. 6,063,057, U.S. Patent Application Publication No. 2004/19323).
When the balloon of the balloon catheters is inflated, in general, a fluid feeder (such as a syringe of medical use) is fitted onto a port located at a handheld side which is connected to the balloon so as to flow a fluid. The balloon is inflated to a required volume by injecting the fluid.
When a gallstone is removed with the balloon catheters described above, a balloon 100 is inflated with a slightly larger diameter than that of a bile duct 110. Thereafter, a gallstone 111 is carried closer to the entry of the bile duct by scraping the gallstone 111 with the balloon 100.
Due to the narrow diameter of the entry of the bile duct, the balloon catheters carrying the gallstone can not be withdrawn from the bile duct without reducing the diameter of the balloon 100. Therefore, in normal practice, an assistant operates the fluid feeder in conjunction with the balloon 100 being pulled by a user; hence the pulling operation is performed by deflating the balloon 100.
However, it is not easy to synchronize the operations of the user and the assistant. If the synchronized operation is not carried out correctly; in this case, if the deflation of the balloon 100 is too fast, the gallstones 111 is separated from the balloon 100 and left in the bile duct.
On the other hand, if the deflation of the balloon 100 is too slow, the balloon 100 may compress the exit of the bile duct 110, or the balloon 100 may rupture.
Further, as the diameter of the balloon becomes smaller and smaller, the diameter will change significantly with a slight operation of the fluid feeder. This is problematic as adjustment of the diameter of the balloon to a desirable size becomes difficult as a result.
In most cases, when a gall stone is removed by using a balloon catheter, various operations including retracting and advancing movements of the balloon catheter, inflation and deflation of the balloon, manipulation of a guidewire and a syringe used for injecting a contrast agent and the like, are required so as to be performed simultaneously; making the user's handheld manipulation at his or her side cumbersome and complicated. Therefore, it is difficult to conduct an entire operation by the user. In addition, even if an assistant assists the operation, burden to the assistant (due to the cumbersome and complicated operation) is large. Furthermore, once the assistant is involved with an operation, it is necessary to synchronize the operation of the user and the assistant.
Furthermore, in a conventional balloon inflation and deflation operation, a diameter of the balloon was maintained to a certain diameter by placing a stopcock between a syringe used for general medical use and a connector provided on a handheld side of the catheter, then a tube connected to the syringe and a tube connected to the catheter are separated by switching the stopcock. In order to adjust the diameter of the balloon at a specific size, a simultaneous manipulation of the stopcock was required while manipulating the syringe for general medical use, and both of the user's hands were required for these manipulations. Hence, the inflation and deflation operation of the balloon was difficult to perform simultaneously so that the entire operation of gallstone removal was cumbersome and complicated.